U.S. stocks opened higher on Monday as the threat of an escalation in Ukraine appeared to lessen and the latest flurry of merger action supported equities. The Dow Jones industrial average was up 0.93 percent at 16,817.36, the S&P 500 was up 0.78 percent at 1,970.35 and the Nasdaq Composite added 30.18 points or 0.68 percent, to 4,495.11.

** DOLLAR GENERAL CORP, $63.03, +9.69 pct

** FAMILY DOLLAR STORES INC, $79.62, +4.68 pct

** DOLLAR TREE INC, $54.623, -1.77 pct

Dollar General offered to buy Family Dollar Stores for $8.95 billion, trumping an offer by Dollar Tree, to strengthen its position as the No. 1 U.S. discount retailer.

The electronics manufacturing services company postponed reporting its fourth-quarter and full-year results, citing accounting issues discovered by the management. The company said the audit committee would investigate whether accounting policies were violated.

** MITEK SYSTEMS INC, $2.449, -19.70 pct

The mobile imaging software maker’s Chief Technology Officer Michael Strange left after two years in office to pursue other opportunities, the company said in a regulatory filing on Friday

Brokerage First Analysis Corp upgraded the healthcare-benefits company’s stock to “overweight” from “equal weight”, according to Theflyonthewall.com. The stock was among the top percentage gainers on the Nasdaq.

** ACHILLION PHARMACEUTICALS INC, $9.49, +2.59 pct

The drugmaker said an experimental hepatitis C drug showed promise in a mid-stage trial and that all patients treated with the drug, ACH-3102, showed no detectable levels of the virus after four weeks.

The fuel components maker cuts 2014 revenue forecast to $335 million-$355 million from $340 million-$360 million. The company

also reports a 21 percent fall in Q2 revenue, partly due to loss of certain contracts and customers.

** SENSATA TECHNOLOGIES HOLDING, $49.01, +6.15 pct

The sensors and electrical controls maker said it would buy Schrader group of companies for an enterprise value of $1 billion to benefit from a growing market for tire pressure monitoring sensors (TPMS).

** LANNETT COMPANY INC, $40.46, +6.75 pct

The generic drugmaker forecast fourth-quarter profit and revenue above analysts’ average estimates. The company said it expected net income attributable to Lannett of between 60-64 cents per share on revenue of about $81 million. Analysts on average were expecting 41 cents per share on revenue of $71.2 million.

** INGERSOLL-RAND PLC, $61.89, +2.21 pct

** CAMERON INTERNATIONAL CORP, $72.52, -0.15 pct

Ingersoll-Rand, a maker of heating and air conditioning systems, said it would buy Cameron International’s centrifugal compression unit for $850 million.

** SEAWORLD ENTERTAINMENT INC, $19, +1.82 pct

Credit Suisse initiated coverage of the theme park operator’s stock with “outperform” rating, according to Theflyonthewall.com. Out of 11 analysts covering Seaworld, five have a “hold” rating, while six have “buy” or “strong buy”, according to Thomson Reuters data.